Science final test Flashcards
Elements
A unique particle of matter or a fundamental building block
Constraint
A limitation on the range of possible solutions
Pure lithium
Fizzes when exploded to water
Pure sodium
React violently enough to create a fire with mixed water
Pure potassium
Explodes when wet. Using method of measurement called daltons
Air it made out of
nitrogen and oxygen particles
Criteria
requirements that must be met for an engineering to be successful
Chemical bond
connection between atoms in more complex particles
Molecule
a group of two of more atoms that held together be chemical bond and the have unique structure and composition
Model
A representation of an object that aspects easier to see atomic composition
Crystal
a solid structure atoms of molecules are reaping three dimensional pattern
Polymer
a type of extended structure that made of smaller repeating subunit a in a chain
Substances
is a matter has constant chemical composition and characteristics
When enough molecules come together
they create a substance
Mixture
is made of different types of atoms or elements or molecules that are not chemically combined
Compound
substance that is made of two or more elements that are chemically bonded smallest unit of compound are atoms
Mixtures do not have
chemical same composition and a lot of varied substances in varying amount
Density
mass per unit volume
Melting point
temperature that substance melts or boils
Solubility
describes how well a substance dissolves in another substance (used to identify the substance)
Flammability
describes how well can substances burn
Melting point changes from
solid to liquid to gas (does not change the amount u have)
How to find volume
density divide mass divide volume
solid
atoms or molecules are closely packed together and touching. Unable to move other than vibrating in place
Liquid
water, atoms or molecules are closely packed and touching but they are not held in a mixed position
Gas
atoms or molecules are separate from each other and can move independently
What affects states of matter?
temperature and pressure
Adding heat to the solid ice cube will give us
Liquid
If we boil the water and if it reaches it’s temperature it turns to
Gas
On top of mountain we have
low pressure or less particles
Sea level is more
high pressure more air particles
how matters change between stages?
cause energy and heat
what if we add heat to solid
`molecules start to speed up and changing to a liquid (melting point)
What if we add heat to liquid?
atoms speed up more and changing to evaporation
boiling liquid
changes to gas by using heat more
gas
atoms slow down allow to come closer became liquid (Condensation)
Three types of elements that make up atoms
Protons, Neutrons, Electrons
Thermal energy
the total energy related to the motion of atoms and molecules in a subject or a sample of matter
Sublime
changes state from solid to a gas do not enter liquid
Temperature
average of kinetic energy
kinetic energy
energy of motion of a movement object
more water
more energy
Heat
makes particles move faster energy from warmer object to cooler object
Condensation
Gas to liquid
Matter
Anything that has mass and volume.
Producers
Can provide their own food and captures energy and matter from its surroundings, sunlight
Producers in Terrestrial Ecosystems
Trees, mosses,ferns (have leaves that adsorbs energy from sunlight)
Radiation
Heating by direct contact between particles
What are conditions that cause chemical reactions?
Heat,cooling,mixing,
Scientific evidence
Evidence of chemical reactions
Atoms in chemical reactions
Atoms regroup in chemical reactions when bonds break in the reactants they reform a new substance.
To describe how atoms regroup we write
Chemical equations
Ways to atoms regroup in chemical reactions
Break down, some joint together, some change places in other groups
Exothermic reactions
Like fireworks exploded that releases more energy to the surroundings than it abosb
Suffix exo means
Turns out or outside
Endothermic reactions
Store energy that absorbs more energy from its surroundings than it releases.
The suffix endo
Means inside so heat goes inside like cooking meat
Synthetic material
An artificial substance or material produced by chemical processes
Biodegradable
Able to be broken down into smaller molecules by biological agents such as bacteria
Synthetic materials made from
Petroleum medicines, polyester fabric, food coloring, food flavoring,rubber, plastic
Producers use photosynthesis to make their own food. What is photosynthesis?
It is a process of using energy from the sun and matter from its surroundings to produce sugars that store energy in chemical bonds
Chorophyll
Green pigment that is essential for photosynthesis. Chlorophyll reflects on making plants green.
Consumers
Organisms that cannot produce their own food
Captures energy from the sun to made sugars
Producers
Uses sugars for energy
Producers and consumers
Obtain matter from the air water and soli
Producers
Obtain matter from eating other organisms
Consumers
Producers get matter from
Carbon dioxide and water from their surroundings
Cellular respiration
is how cells get energy. It takes in glucose and oxygen, and changes them into energy while also producing carbon dioxide and water as waste. This process happens in three steps: breaking down glucose, a cycle that helps produce energy, and using oxygen to make more energy.
Equation for cellular respiration
Sugar+oxygen—carbon dioxide+water+energy
The law of conservation
of matter is a scientific law stating that the amount of matter in a closed system always stays the same, although matter may change form. A scientific law is a statement, based on evidence from repeated observations, that describes an aspect of the universe that is consistent and predictable.
There are small exceptions to the model of Earth as a closed system.
Some matter does leave Earth when humans send spacecraft into space. And space objects, like meteors, can bring small amounts of matter into the system. Even with these exceptions, scientists find the model of a closed system useful for understanding Earth’s ecosystems.
The water cycle
is a model that describes how water molecules move among Earth’s ecosystems and the atmosphere.
The water molecule in the soil is absorbed
by producers, such as aquatic plants, where it becomes part of an aquatic plant cell
Other water molecules might be used
in photosynthesis to make oxygen gas and sugar molecules. A grazing manatee eats the grass, taking in the water molecule.
Decomposers consume the manatee’s wastes and return the water molecule to the soil.
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When sunlight warms the water molecule in the soil, it enters the atmosphere as water vapor, starting the cycle again.
Global cycles of matter
are important to maintaining healthy ecosystems on Earth because they make different forms of matter available to living things.
Like water molecules,
atoms of carbon move among the living and nonliving parts of ecosystems.
Start with carbon dioxide molecules in producers. Follow the path of a carbon atom through different parts of Earth’s ecosystems.
Carbon atoms become part of different carbon-based molecules through photosynthesis, cellular respiration, and other processes.
The carbon cycle
is a model that describes how carbon-based molecules move among Earth’s ecosystems and atmosphere.
What carbon molecule is present in the breath you exhale?
It uses other carbon-based molecules for energy and exhales carbon dioxide into the atmosphere. It uses other carbon-based molecules for energy and exhales carbon dioxide into the atmosphere.
Carbon is incorporated into living things in the ecosystem through
photosynthesis
How can carbon move from fossil fuels to the atmosphere?
When carbon atoms are stored under layers of soil for millions of years, they may form fossil fuels, which humans use as a source of energy.
Carbon in living things is released
into nonliving parts of an ecosystem through cellular respiration
How can carbon move from a manatee to a lake?
This manatee eats aquatic plants and uses some of their carbon-based molecules to build its body structures. It uses other carbon-based molecules for energy and exhales carbon dioxide into the atmosphere. Some carbon dioxide remains dissolved in the water and is used by the aquatic plants that are food for the manatee.
nitrogen cycle
is a model that describes how nitrogen-based molecules move among Earth’s ecosystems and atmosphere.
What percent of Earth’s atmosphere is made up of nitrogen gas?
78 percent
What common molecules are made with atoms of nitrogen?
Farmers often plant crops like peanuts to improve nitrogen concentration in soils because these plants house those bacteria in their roots.
What does nitrogen fixation do?
Earth that can convert nitrogen in the atmosphere into more complex nitrogen-based molecules. This process is called nitrogen fixation and it can happen in two different ways.
ammonia
Bacteria for nitrogen cycle
nitrifying bacteria,
can convert ammonia into nitrates. Most producers need nitrates to grow and form important nitrogen-based molecules in their bodies.
How can nitrogen from organisms get back to the atmosphere?
When the peanut plant dies, decomposers, such as bacteria, break down the proteins in their bodies, leaving nitrogen-based molecules like nitrates and ammonia. Other bacteria, called denitrifying bacteria, convert those nitrogen-based molecules into nitrogen gas. The atom of nitrogen is again part of a molecule of nitrogen gas. It has returned to the atmosphere and completed the cycle.
Defining Criteria
Criteria describe what must be done to meet the goals of the project.
Reforestation
is the re-planting of forests
Constraints
are limitations on an engineering solution.
Fossil fuels
are natural energy sources
Cellular respiration releases energy to
Chemical bonds of dugar
Photosynthesis captures energy from
Sun
Food web
A model that shows feeding relationships between populations in ecosystems
Direct affect
Increases population of predators but decreasing population that they prey
Indirect affect
Interaction where one population affects the other of another through its effect on a third population
Phytoplankton
Energy enters the food through phytoplankton
Zooplankton
Use energy and lose energy through wastes and heat
